For over twenty years, McDonald's Corporation, which has well-known restaurants, has employed a characteristic roof design as part of its "signage". The McDonald's roof design consists of top, middle and lower roof portions. The top portion is horizontal and flat, spans the restaurant and forms the deck of the roof. The middle and lower roof portions are angled and intersect to form a valley. The middle and lower roof portions have disparate slopes; the middle portion is pitched at a greater angle than the lower portion.
During this period, McDonald's Corporation has used lamp-mounting elongate roof fixtures to illuminate the roofs of its restaurants. These light fixtures typically are positioned in or under a plurality of distinctive parallel-spaced roof beams which extend up the roof and over the lower and middle roof portions. All of such prior art roof-beam lighting systems have significant problems and disadvantages. This invention overcomes such problems and disadvantages.
For example, one version of such roof fixtures, still in wide use, does not completely illuminate the roof and is difficult to service. This system has as its light source either one centered fluorescent tube or a pair of parallel tubes, such tubes being mounted in spaces provided along the roof beam. Light from these tubes is emitted laterally from the roof beams onto the middle and lower roof portions which are adjacent to the beams and light fixtures. These fixtures give fairly intense light to the roof immediately adjacent to the beams, but provided very little light to most of the roof. In addition, service for such light fixtures is rather difficult and inconvenient because service personnel may be required to stand on the sloped roof portions to change a lamp or repair a fixture.
Still another of the prior roof-beam lighting fixtures uses what is known as a "Light-Pipe" optical system to achieve essentially the same result. The light from these fixtures, like that from the aforementioned fluorescent fixtures, is quite weak over most of each lower and middle portion of the roof.
Another McDonald's roof-beam lighting system, which is the subject of U.S. Pat. No. 5,081,567 (Weiss), involves placement of a bulb inside the roof beam at the lower end of the beam and adjacent to windows formed on either side of the beam. Such lamp is oriented along the beam and projects light through the windows onto the roof. This system provides brighter, but uneven, illumination and is rather inefficient in operation. Furthermore, such systems are considered to cause glare to observers at certain positions around the roof. Another problem is that such system has its ballast located at a position remote from the lamp, which can complicate service.
Another system overcoming certain of the problems of the Weiss system is described in U.S. application Ser. No. 07/981,605 (Ruud). Such system has improved brightness, efficiency and serviceability, but shares certain of the other problems mentioned above with respect to the Weiss system, particularly with respect to evenness of illumination.
All of the aforementioned roof-beam lighting systems share still another problem: All such lighting fixtures of the prior art are connected to or form parts of McDonald's roof beams. This tends to make them expensive, tends to impose limitations on efficiency of light use, and can complicate service. Furthermore, the roof beams themselves require structure which otherwise would not be needed.
An improved roof-lighting system for illuminating roofs of the disparate-slope type common on McDonald's Restaurants would be an important advance.